**Core Concept**
The triple test, also known as the triple screen, is a prenatal test used to detect potential fetal abnormalities, particularly Down syndrome (Trisomy 21), neural tube defects, and other chromosomal disorders. This test typically involves a combination of three biochemical markers measured in the maternal serum.

**Why the Correct Answer is Right**
The triple test includes three key components: alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG), and unconjugated estriol (uE3). These markers are essential in assessing the risk of fetal anomalies. Alpha-fetoprotein (AFP) is a protein produced by the fetal liver and yolk sac, while hCG is a hormone produced by the placenta. Unconjugated estriol (uE3) is an estrogen produced by the fetal adrenal glands and the placenta. The levels of these markers are measured in the maternal serum during the second trimester of pregnancy.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not listed, so we can assume it is not relevant to the triple test.
**Option B:** This option is also not listed, so we can assume it is not relevant to the triple test.
**Option C:** This option is not listed, so we can assume it is not relevant to the triple test.
**Option D:** This option is also not listed, so we can assume it is not relevant to the triple test.

**Clinical Pearl / High-Yield Fact**
The triple test is not a definitive diagnostic tool, but rather a screening test to identify pregnancies at high risk for fetal abnormalities. A positive result may lead to further diagnostic testing, such as amniocentesis or chorionic villus sampling (CVS).

**Correct Answer:** D.